Coke oven with internally heated movable heating walls



Oct. 3, 1939. F, PUENING 2,174,832

coms-OVEN WITH INTERNALLY HEATED MovABLE HEATING WALLS Filed Sept. 5, 1956 4 Sheets-Sheet l 1v1/enfoui" Get. 3, 1939. F. PUENING 2,174,832

COKE OVEN WITH INTERNALLY HEATED MOVBLE HEATING WALLS Filed Sept.' 5, 1936 4 Sheets-Sheet 2 Oct. 3, 1939. F, PUENlNG 2,174,832

COKE OVEN WITH WTERNALLY HEATED MOVABLE HEATING WALLS Filed Sept. 5, 1936 4 Sheets-Sheet 3 y se 96 .97 J8 99 Inventor F. PUENING Get. 3, 1939.

Filed Sept. 5, 1936 4 Sheets-Sheet 4 Patented Oct. 3, 1939 UNITED STATES PATENT GFFICE Franz Puening, London, England Application September 5, 1936, Serial No. 99,600

In Germany September 7, 1935 10 Claims.

The invention relates to coke ovens especially for low and medium temperature coking in which movable internally heated hollow metal heating walls are employed. More especially it relates to the method of heating these heating Walls.

In ovens of this type, already known, it has been proposed to heat the movable walls by rst generating hot gases at a place outside the walls and afterwards circulating the hot gases through the walls by means of hollow exible connections. This arrangement requires considerable space and causes great expenses through radiation of heat and mechanical energy required for propelling the gases. Furthermore, it is expensive because of the required large flexible conduits for conveying the heating gases. In case of large heating walls, these conduits become so large that in order to accommodate the conduits, an increased width of the heating walls themselves is required, thus increasing the dimensions and the cost of the entire plant.

In a pending application, I have already proposed to arrange gas burners inside of the movable walls for the purpose of supplying additional fresh heat to the heating gases circulated through the walls. However, the arrangement proposed and the advantage obtained thereby has proved insulicient to permit the construction of walls of such large size and such ease of operation that a sufficient reduction in the cost of operation and capital would result to permit for instance the use of the coke as boiler fuel.

In the present improvement the disadvantages of the older ovens are successfully overcome and their insufliciencies removed. More especially the following improvements are obtained: The heating walls are fully guarded against local overheating, in spite of the fact that the heating is accomplished exclusively by burners arranged inside of the walls. The burners are fully and permanently accessible for ignition and observation. The volume of old heating gases circulated through the heating walls in order to vdistribute the coking heat has been reduced to a very small fraction of that previously used. The loss in heat and the cost of power to accomplish this circulation is correspondingly reduced. In case of damage to the burners, which is always possible because of the refractory material of which they are made, the burners together with their manifolds can at once be removed and replaced, without any interruption in the operation of the wall, which is important because such damage is liable to cause overheating or underheating of the wall. In case of a change in the kind of coal to be carbonized, requiring for instance a lowering of the carbonizing temperature from 600 C. to 525 C., the necessary reduction in the heat supply of the burners can .at once be executed due to the ease with which the burners are accessible, exchangeable or adjustable.

Furthermore, the present improvement finally removes all obstacles to any desired increase in the size and therewith in the coking capacity of the individual heating wall. In all previous arrangements it was practically impossible to obtain walls of very large dimensions, because of the difliculties mentioned and thus the aim of producing cheapest coke for boiler uses was heretofore not attainable. The new arrangement now makes it possible to give the wall enormous sizes, thus reducing the number of the walls in one unit, thus simplifying the charging and discharging machinery, also reducing the number of ovens in a battery thus reducing the cost of the entire equipment and of the operation.

The drawings show two embodiments of the invention:

Fig. 1 shows a sectional elevation of a large heating wall and the means for heating it.

Fig. 2 shows a sectional plan view ofthe same arrangement cut on the lines II-II of Fig. 1.

Fig. 3 shows a horizontal cut on the line III--III of Fig. 1.

Fig. 4 shows a vertical cut along the line IV-IV in Fig. 1.

Fig. 5 shows a partial sectional elevation through the wall shown in Fig. 1, but with the ejector shown in Fig. 1 replaced by an electrically-operated fan.

Fig. 6 shows a sectional elevation through the second embodiment.

Fig. 7 shows a sectional plan View of the embodiment in Fig. 6, taken through lines VII--VII of Fig. 6.

Fig. 8 shows an enlarged sectional view of the stuffing boxes used in all cases.

Figs. 9-10-11 show details of the burners in case of Fig. 6.

The metal heating walls 6 are arranged inside the enclosure 4, which consists of the side walls I and 2, the front wall 3, and a similar rear wall, and which is closed on topy by cover 5 and at the bottom by a removable door 5a. The coal chambers l2 are arranged between the heating walls, which are equipped with vertical ribs 'i and 8. Each heating wall 6 is supported at the upper left-hand corner by means of a U-shaped bracket I3, I5, which dips down through a water seal I4, and extends to the left where it is centered on a vertical pivot I6 around which it can be swung. At the upper right-hand corner the same wall is supported by a second bracket l1, I8, which dips through a similar water seal, and which has an extension equipped with a shaft and a roller I9 which is supported on ancommon rail 2i. Ihe bracket I5 also carries a roller I1, which is supported on a similar rail 2|.

Each heating wall is divided by two groups of baffle plates 22, 23, and thus is created a system' of connected heating flues or compartments 24,4v

25. The heating gases contained in this system of heating fluids is kept at the required temperature by means of burners 33, 4I, 42, 43, which receive their fuel consisting of air and gas in mixed form through lines 34. For theforcible recirculation of the heating gases inside of the wall an ejector 26 is provided, which receives the driving gas through pipe 21. The ejector action of .the compressed driving gas causes the aspiration of a portion of thelheating gas contained'in the uppermost iiue 24 drawing them through the inlet nozzles 28 yand pressing them through the ejector throat 20 into the crossflue 29 and further'through the .flat yvertical ues 36 and the horizontal bottom flues 3| from where the gases finally emerge'through opening 32 thusentering the lowest ue ofthe heating wall.- AThe action of the ejectorthus causes a continuous recirculation of the heating gases contained in the heating wall while the gases not recirculated escape into the chimney through the opening 46. By provision of a great number of burners, which are substantially arranged in series, the volume of the heating gases that -must be circulated is reduced to a minimum; nevertheless a uniform heating of the entire heating wall is assured because each burner now furnishes only a small amount -of heat and ank .irregularity in this amount is therefore not able to cause an objectionable change in the temperature of the stream of circulating gases.

All burners are of the surface combustion type. They are arrangedv insuch a manner that. the hot gases issuing from them are surroundedv and enveloped by the recirculated gases, so that the new hot gases cannot directly touch the metal surfaces. Protecting shields 44 may be interposed between the burners and the surfaces Yof the `walls or each burner may be surrounded by a small shield.

`Ihearrangement of a great number of burners in series has the advantage that thevolume of gases to be recirculated is reduced in proportion tol the number of burners because the reduction of the distance between consecutive burners governs the amount of heat ,to be carried by the recirculating. gases, whichy only needsto be Ysuicient to supply the small heating surface between the burners. Burners mayalso be arranged in the ues 24. The bur-ner groups 4 I and 43 are arranged in portions of the heating flues in which the heating gases travel in an upward direction, and therefore they impart to the gases at these points va Ybuoyancy which` facilitates their travel,

and reduces thevmechanicall energy to be furnished by the ejector.

' The burners 33, together with their manifolds 39 can. be observed through the tubular extensions 35, which are of such a diameter that the burners, together with their manifolds, can be removed from Athe -w'alls and replaced immediately by a new one, so that not even an interruption of the operation is required.

The tubular extension 35 is sealed against a tubular extension 36 protruding from side wall I of the enclosure in a gas-tight flexible manner by means of a stuing box arrangement 31 shown in greater detail in Fig. 8 and described later.

The surplus heating gases notrecirculated by the ejectorp-ass through .the chimney connection 46 into the lower part 41`of a chimney. The

v chimney flue 46 consists of the tubular extension Al'which is insulated on the inside.

It passes through'another tubular extension 49 fastened to the outer shell of side wall I against which it is sealed in a gas-tight and flexible manner, by stuffing box 48, which is similar to the arrangement '31 shown in Fig. 8. This exible stuing box arrangement is located in the same vertical axis 38 in which the pivot I6 and also the other flexible seals 31 are located.

The pipeg21 which carries the compressed gas for the operation of the ejector is located in the chimney flue 46, and in this manner the compressed gas becomes pre-heated in counter current against the surplus gases leaving the heating wall.` In order to increase the temperature of the compressed gases still further a special heat exchanger 5I may be provided. For the operation of the ejector, either steam or compressed air, or'

compressed stack gases may be used. In the latter case the heating gases may be taken from the chimney 41 through pipe 52, and after passing through a scrubber 53 where they are cooled and washed, they pass through a small heat exchanger 54 where they are dried, and thereafter through a gas compressor 55, and thereafter through a distributing manifold 56 and a larger heat exchanger 5I, and finally through the pressure pipe 21 to the ejector.

The scrubber 53, the pre-heaters 54 and 5I, and the compressor 55, may be used in common by the entire battery of heating ovens, and the compressor may be located in the pump room of the plant, where it is under the control of a competent mechanic. It is evident that this arrangement is'greatly superior to the older arrangements where very large fans which must carry large Volumes of hot combustion gases of 600 C. or more,`are provided for each oven.

Instead ofthe ejector shown,-other small fans may be used. Fig. 5 shows'the ejector replaced by a fan or propeller 51 which is driven by an electric motor 6I. The connecting shaft 58 between the motor'and the propeller passes through a tubular elongationV 65 of the motor casing, which carries a bearing at its extreme end which is kept cool by a continuous flow of lubricating oil through the elongation, entering through pipe .66, and leaving through pipe 61. The flow of heat into the oil is reduced by the insulation 64, inside the tub-ular piece 59, which again is sealed against the. outer enclosing wall I by means of an extension 63 and a stuffing box arrangement 62 similarto the one shown in Fig. 8, and located again within the vertical axis 38. The fan 51 .discharges the recirculated gases directly into the intake 66 of the return flue 29.

The horizontal baiiie plates 22 and 23 are shorter inthe upper portion of the wall where the Vquantity of the heating gases is increased by the addition of new heating gases supplied by the burners. For the same reason the vertical height of the horizontal lues 24 and 25 is increased in the upper portion of the wall. The return ue 29 is sub-divided into flat sections 30 in order to reduce the obstruction to the recirculated gases, and also in order to enlarge its surface so that the returned gases become well preheated before they enter the lowest flue through openings 92. It is, of course, possible to use only one return flue 30 of larger cross section and to provide gas burners in this flue for raising the temperature of the return gases.

In those flues 24 in which no burners are provided special displacement bodies 11 may be arranged as shown in the lowest flue 29 of Fig. 1 and Fig. 4. These displacement bodies have the eifect of increasing the speed of travel of the heating gases and of forcing them to pass in greater proximity to the coking surfaces 9 and l l, so that the heat transfer is increased at these points. Flues 24 also show a smaller height than flues 25, so that their heating surfaces are smaller.

The electric motor shown in Fig. 5 may be replaced by belt drive or by a small turbine. The heating flues which are shown in series may be combined in pairs, the pairs being arranged in series. Instead of using one ejector or fan it is possible to use several.

Furthermore, it is not necessary that the ejector or fan be arranged in the uppermost flue. It may be arranged in the middle of the heating wall or at the bottom, and the gases aspirated may be led to the intake of the fan by means of a suction flue with the result that the discharge flue is correspondingly shortened. The general motion through the system of flues 24 and 25 may be upward or downward. The combustlon chambers of the burners may have various forms and positions and the manifolds 39 may be insulated, as shown in Figs. '7, 8 and 9.

The embodiment shown in Figs. 6 and '7 is able to work without special means for recirculation of the heating gases. All the essential advantages described before are however retained. The vertical heating walls 89 contained in enclosure 98 are divided by horizontal partition plates 8| into superposed horizontal heating flues 82, 83, 99, 85. Burner manifolds 8B enter into these iiues through one of the narrow side faces of each heating wall. These burner manifolds are supported by the partition plates 8|, the partition plates in turn resting on narrow internal ledges 81, to which the partition plates are fastened by means of long vertical rods 88. The horizontal ledges 81 are welded to the inside surfaces of the heating walls. The heating wall surfaces in contact with the coal have a form resembling so called corrugated iron sheets, with the distinction that the protruding hollow rigdes 98 of the corrugations have a triangular shape, while the bottoms of the grooves between the ridges are flat. Ihe horizontal ledges 81 on which the bale plates 8| are resting are straight fiat iron bars which do not enter into the hollow triangular spaces 98 behind the ridges 98 and thus are left free triangular openings 96 between the edges of the ledges 81 and the inner surfaces of the hollow ridges 98. These openings 96 serve as passage ways for the combustion gases thus connecting with each other the superposed heating flues 82, 93, 99 and 85.

The combustion gases developed by the burners in the uppermost horizontal chamber 82 due to their buoyancy rise to the ceiling 95 of this chamber, whereupon they turn and due to the chilling action exerted by the coal pass vertically down over the heating surfaces of the wall, and thereafter pass through the triangular Aopenings 96.

These triangular openings formed between the horizontal ledges 81 and the ridges 98 of coking surfaces of the heating walls also serve to increase the heating surface of the walls and improve the coke quality. In case of the outer vertical surfaces 99 of the two outer walls which are not used for the coking operation, these hollow ribs are omitted and special openings 91 are provided in the ledges 81 to permit the heating gases to descend from the upper compartments down to the lower ones.

The surplus heating gases discharged from the upper compartment 82 through the openings 96 and 91 now lenter the lower compartment 83 where new hot products of combustion are introduced through burner bar 86, and thereafter they continue their downward travel to compartments 84 and 85. This last compartment may also have a burner bar of its own. The surplus combustion gases finally pass from the lowest compartment 85 through the chimney connection |09 into the suction flue of a chimney or a heat exchanger, which are not shown.

The embodiment shown in Figs. 6 and '1, as stated before, can work without a fan for the recirculation of the combustion gases relying upon the recirculation created in each compartment by the chimney action of the burners. For this purpose the burner manifolds 88 extend over the entire horizontal length of the heating walls and carry a great number of small burners. These burners are of the type mentioned before belonging to the class of surface combustion burners. A preferred form of these burners is shown in Figs. 9, l0 and l1. .It is, however, possible to employ a fan in connection with the walls shown in Figs. 6 and '1 which would draw a portion of the waste gases for instance from the bottom compartment 85 and transport them into top compartment 82, whereby the fan or ejector would again be arranged inside of the heating wall.

A preferred form-of the combustion chambers used is shown in Figs. 9, l0 and 11. Insulating material |29 is packed around the burner bar 86 and held together in a metal trough |2|. Special cooling coils |22 and |23 may be arranged in proximity to the burner manifold 89 in order to keep the fuel gases at a low temperature. The cooling coils may be -held to the burner bar by wires |24. Surface combustion chambers |25 are xed above each fuel nozzle 29. The fuel and air mixture issuing from these nozzles rst enters an expansion chamber |21 and thereafter impinges upon a baflie plate |28 orother bodies which serve to deflect the burning mixture and to accelerate the combustion. Each combustion chamber l 25 is maintained in its position by means of two small posts |29, which are welded upon cover plates |39 which rest upon the upper edges of the metal trough |2| containing the insulating material. rllhe hot new combustion gases issue from openings lill, which point toward each other so that the names spread from one combustion chamber to the other thus facilitating the ignition of all the burners.

At the points where the heating gases or the means for effecting the recirculation Lare introduced into the oven or where the waste gases are removed, eective seals are provided for sealing the heating walls against the outer enclosure. These seals are all of the same character in both embodiments. Tubular extensions 18 or 99 are Welded to the narrow side faces of the heating walls and into these have been screwed further tubular extensions 35 or 9|. The outer enclosures I or 92 are also equipped with tubular extensions ameter than the extensions of the heating Walls. These two types of concentric extensions are thereafter sealed against each other as shown in detail in Figs. 8 and 8a.

The outer extension 93 shown in Fig. 8 is equipped with a vertical ange |4IJ and the inner extension tube 9| belonging to the heating wall is surrounded by two ring-shaped bodies |4`| and Y |42, which hold packing rings |43 and |44 in such a position that they can be pressed against the iiange I4!) and against the inner extension tube 9|. Two yokes |45 are provided, which subject the packing rings to a gentle pressure by means of bolts |46.

Fig. 8a shows a refinement of this arrangement in which a part-spherical body |41 is provided on the outside of extension tube 9|, which permits the swinging of the heating wall over a greater angle. The opening in flange |40 through which the inner extension tube I penetrates is of such size that it permits considerable movement of the heating-wall. This movement which is due to heat expansion of the wall takes place mainly in a vertical direction downward, and therefore the opening in flange |40 is especially large below pipe-9|, but the opening is also large enough to permit a horizontal expansion of the heating walls by which they become thicker. Another horizontal expansion of the heating walls from left to right is taken care of by tube 9| sliding in the direction of its axis through the stufng box arrangement.

The tubular extensions of the heating walls in Fig. 1 are composed of the two pieces 18 and 35 while in Fig. 6 they are composed of the two pieces 99 and 9|. Of these the pieces 18 and B are welded to the walls while the pieces 35 and 9| are screwed into the pieces 'I8 and 99. This arrangement facilitates the removal of a wall from the enclosure. If such removal becomes necessary the outer tubular pieces 35 or 9| are removed, whereupon the entire wall can be lifted out of the enclosure.

All these tubular extensions and their seals are so located that their centre lines pass through the vertical axis 38 in Fig. 1 or through axis |99 in Fig. 6, around which the heating walls are swung when they are spread apart for the purpose of the discharge of the coke. All these ilexible seals are arranged in the open and are fully accessible and reliable and constitute a great iinprovement over the previous conditions.

The new carbonizing oven just described has the advantages enumerated at the beginning. The use of great numbers of small combustion chambers in each of which a perfect combustion is performed before the products of combustion issue into the surrounding flues has the advantage that the heat value of the fuel is fully utilized. Furthermore, a serious danger of explosion is avoided. Certain coals require a very low temperature of carbonization, for instance, 525 C., which lies below the temperature of ignition of certain fuel gases. In case of incomplete cornbustion the unburned gases entering the large heating iiues maintained at 525 C. will immediately drop to nearly this temperature with the result that combustion will remain uncompleted. This condition is made worse in case of lean fuel gases, such as producer gas. It is, therefore, possible that explosions of unburned gases take place. Furthermore, the presence of unburned fuel gases and oxygen exerts a corrosive effect upon vthe metal of the heating walls. vAll these disadvantages are overcome by the utilization of large numbers of small effective combustion chambers in which complete combustion is perfected before the burnt gases enter the heating flues. Furthermore, because the volume of old heating gases to be recirculated, is now reduced to a fraction of the previous requirements the important advantage is obtained that the cross sectional area ofthe interior heating flues can now be made much smaller with the result that the walls can be made much thinner and therefore cheaper.

I claim:

1. In a coke oven, a plurality of movable, internally heated heating walls, coal chambers formed between them, an enclosure surrounding said walls and said coal chambers and adapted to collect the products of carbonization, heating flues in said walls, means for heating the heating gases contained in said ilues, said means consisting of burners arranged in said flues and burner pipes carrying fuel gas and air for combustion to said burners, said burner pipes entering into said nues through one ofthe vertical side walls of said enclosure and thereafter through one of walls adapted for recirculation of the heating gases contained in said ues past said burners and a conduit communicating with each of said walls and adapted for leading the waste gases away from said walls.

2. Coke oven for low or medium temperature coking, comprising hollow, movable vertical metal heating walls having interior heating spaces between their vertical metal surfaces, an enclosure surrounding said walls and separating them from the space outside, a coal vapor collecting space between said enclosure and said walls, a plurality of superposed horizontal burner pipes entering into said heating spaces through said enclosure and through said coal vapor space and through one of the vertical surfaces of each of said walls, said burner pipes carrying new fuel gases and air to one or more burners in said interior heating spaces of said heating wall, sealing means surrounding portions of said burner pipes and adapted for movably sealing said interior heating spaces, said vapor collecting space and the outside space against each other, and conduits communicating with said walls and adapted for the off-flow of the excess combustion gases away from said walls.

3. Low or medium temperature coke oven, comprising an enclosure containing movable metal heating walls, with interior heating spaces therein between essentially parallel vertical metal coking surfaces, openings in one of the side walls of said enclosure, hollow tubular extentions of the heating walls, extending through said openings in said enclosure, gas-tight flexible seals between the edges of said openings and the outer surfaces of said tubular extensions, said flexible seals being adapted for a swinging and a vertical motion of said tubular extensions inside said openings, burner pipes entering through said tubular extensions into said interior heating spaces, said burner pipes adapted to supply fresh fuel gases vand air for combustion to said interior heating spaces and exit conduits communicating with said interior heating spaces and adapted to conduct the surplus waste gases away from said Walls.

4. Low or medium temperature coke oven, cornprising an enclosure for the collection of gases of distillation, hollow movable essentially vertical heating walls in said enclosure, said walls containing gas burners, means for swinging each wall around a vertical axis, said axis lying outside of said enclosure, pairs of substantially concentric hollow' extensions protruding from each of said walls and said enclosure to said vertical axis, the outer member of one of said pairs of substantially concentric extensions being fastened to the enclosure and having an interior diameter much in excess of the exterior diameter of the inner member fastened to the heating wall, means for sealing the inner extension against the outer at a point lying within the Vertical swinging axis, said means comprising a flexible circular packing on the outside of the inner extension for the swinging motion of said wall and a second iiexible packing movable in a direction adapted to permit the vertical heat-expansion of the wall, burner pipes for the adduction of new fuel gases and combustion air to said gas burners, said burner pipes entering through the interior of said extensions and a gas exit lue communicating with said heating walls and adapted to lead the' surplus waste gases away from each of said walls.

5. Low or medium temperature coke oven comprising an enclosure containing movable internally heated metal walls, a plurality of gas burners in each of said walls, power-operated means in each of said walls and adapted forcreating a forceful recirculation of the combustion gases contained in each of said walls, past said burners and conduits communicating with said walls and adapted to carry the surplus waste gases away from said walls.

6. Low or medium temperature coke oven comprising an enclosure containing internally heated movable heating walls, each of said walls containing a plurality of gas burners and a compressed gas or steam-operated ejector for the recirculation of heating gases inside of said wall and exit conduits communicating with each of said walls adapted to carry the surplus waste gases away from each of said walls.

7. Low or medium temperature coke oven comprising an enclosure containing movable internally gas heated heating walls, each heating wall containing a closed system of flues consisting of a series of heating lues and a special return ue, which system is adapted for a continuous circulation of the heating gases through all of said flues and comprising a power-operated mechanical device built into said system of flues for causing said circulation, gas burners arranged inside said heating flues, burner pipes adapted for carrying fuel gas and combustion air from the space outside of the enclosure to said gas burners, seals in combination with the burner pipes, adapted for separating the space outside the enclosure, and the space inside the enclosure from each other and from the system of flues in the heating walls, said seals being adapted for permitting the motion of said heating Walls inside said enclosure, an exit conduit communicating with each wall and adapted to carry waste gases away from each wall.

8. Coke oven with movable, internally heated heating walls inside an unheated enclosure, in

which each of said walls swings around avvertical axis of its own, all said vertical axes lying near one of the outside walls of said enclosure, openings in said enclosure, tubular unheated wall extensions from said walls to said vertical axes, said extensions adapted to serve as tunnels for the introduction of fuel and air lines into said walls, means for movably sealing said wall extensions against the edges of said openings in said enclosure at points located within said axes, fuel and air supply lines passing through said extensions into the interior of said walls and connected to burners inside of said walls adapted to burn said fuel gas and air and conduits commlmicating with the interior of said Walls and adapted for the oir-flow of surplus waste gases away from said walls, said conduits passing through said openings in the wall of said enclosure and sealing means surrounding said conduits at the point of their passage through said enclosure wall, adapted for movably sealing the outside surface of said conduit against the edges of said openings in said enclosure.

9. Coke oven for low or medium temperature coking, comprising hollow, movable vertical metal heating walls having interior heating spaces between their vertical metal surfaces, an enclosure surrounding said walls and separating them from the space outside, a coal vapor collecting spacebetween said enclosure and said walls, a plurality of superposed horizontal burner pipes entering into said heating spaces through said enclosure and through said coal vapor space and through one of the vertical surfaces of each of said walls, said burner pipes carrying new fuel gases and air to one or more burners in said interior heating spaces of said heating wall, sealing means surrounding portions of said burner pipes and adapted for movably sealing said interior heating spaces, said vapor collecting space and the outside space against each other, and conduits communicating with said walls and adapted for the off-flow of the excess combustion gases away from said walls, each conduit penetrating the vapor collecting space and the enclosure and being at the points of penetration equipped with sealing means adapted for movably sealing the coal-vapor collecting space against the interior heating spaces and the outside space.

10. Coke oven for low or medium temperature coking, comprising hollow, movable vertical metal heating walls having interior heating spaces between their vertical metal surfaces, an enclosure surrounding said walls andseparating them from the space outside, a coal vapor collecting space between said enclosure and said walls, a plurality of superposed horizontal burner pipes entering into said heating spaces through said enclosure and through said coal vapor space and through one of the vertical surfaces of each of said walls, each burner pipe extending substantially over the entire horizontal length of said wall and being adapted to carry new fuel gas and combustion air to a plurality of burners over the horizontal length of said wall, sealing means surrounding portions of said burner pipes and adapted for movably sealing said interior heating spaces, said vapor collecting space and the outside space against each other, and conduits communicating with said walls. and adapted for the oiT-iow of the excess combustion gases away from said walls.

FRANZ PUENING.

Cil 

